Anti-slip bathtub bottom



FIG. 1 is a top plan view of an ornamental design of an anti-slip bathtub bottom embodying my new design; and

FIG. 2 is a cross-sectional view taken on line 2--2 of FIG. 1;

The broken line showing of a bathtub in FIG. 1 is for purposes of illustration only. 

The ornamental design for an anti-slip bathtub bottom, substantially as shown and described. 